This invention relates to engagement and disengagement timing controls for a fluid-operated piston of a friction torque transmitting device, and more particularly, to such controls which rapidly exhaust the fluid-operated piston and specifically to downshift controls that separate the piston exhaust fluid from the timing device exhaust fluid during disengagement.
Prior art controls seeking to fluidly separate the accumulator from the friction device, use a valve member, separate from the shift valve, to control fluid flow to and from the friction device and the accumulator. With these controls, the accumulator is exhausted through the feed restriction and/or a ball check to the exhaust passage of the friction device. While these controls may provide for slightly more rapid friction device exhaust, they do not permit rapid accumulator exhaust.